Jeremy Morris, a pioneer of the aerobics movement and who proved exercise is heart-healthy, dies at 99½

Jeremy N. Morris, a British epidemiologist whose comparison of heart-attack rates among double-decker bus drivers and conductors in London in the late 1940s and early ’50s laid the scientific groundwork for the modern aerobics movement, died Oct. 28 in Hampstead, London. He was 99 ½.

“He always insisted on adding the ½,” said his daughter, Julie Zalewska.

The cause of death, she said, was pneumonia and kidney failure.

It had long been surmised that exercise and a healthy heart were correlated.

“You can go back to ancient physicians and philosophers like Hippocrates and Siddhartha who said exercise is good for you, but they didn’t have any data,” Steven N. Blair, a professor of exercise science and epidemiology at the University of South Carolina, said in an interview on Thursday. “Jerry was the guy who did the systematic research that invented the whole field of physical activity epidemiology.”

“His impact was huge,” Dr. Blair added.

Terence Kavanagh, an internist and professor of exercise science at the University of Toronto, agreed, saying, “The work he did set the tone for future research.”

Dr. Morris surmised that the proof could be found on the stairs of those double-decker buses. In 1949, he began tracing the heart-attack rates of hundreds of drivers and conductors. The drivers sat for 90 percent of their shifts; the conductors climbed about 600 stairs each working day. Dr. Morris’s data, published in 1953, indicated that the conductors had fewer than half the heart attacks of their sedentary colleagues.

In a follow-up study, Dr. Morris found that a lower incidence of heart attack among people doing physical work was not, for the most part, related to other factors, like body type. Transport for London, the city’s transportation agency, provided him with the sizes of the trousers it supplied to its workers. His data indicated that the conductors’ waistbands were smaller, but that their protection against heart attack could not be explained by their relative leanness. They had a lower risk of heart attack whether they were slim, average size or portly.

To corroborate his findings further, Dr. Morris did a study of postal workers. Comparing those who delivered the mail by walking or riding bicycles with the clerks behind the window at the post office and the telephone operators, he found that the deliverers also had a far lower risk of heart attack.

Then, in the 1960s, Dr. Morris conducted an eight-year study of the overall physical activity of 18,000 men in sedentary civil service jobs. The data showed that those who engaged in regular aerobic exercise — fast walking, cycling, swimming or other sports — reduced their risk of heart attack by half.

In 1972, in Atlanta, Dr. Morris and Dr. Ralph S. Paffenbarger Jr. were awarded the first International Olympic Committee Medal in sports science.

Jeremy Noah Morris was born in Liverpool on May 6, 1910, into a family of Jewish immigrants who had fled pogroms in eastern Poland. His father, Nathan, was a Hebrew scholar. After arriving in England, the family took the last name of the captain of the ship that had brought them to Liverpool. Jeremy was born within weeks of the arrival. The family then moved to Glasgow.

Jeremy began to exercise early in childhood. His father would take him on four-mile walks, then reward him with ice cream.

After attending the University of Glasgow, Dr. Morris completed his medical degree at University College London Hospital in 1934. In World War II, he served in India and Burma with the Royal Army Medical Corps, rising to lieutenant colonel. In 1948, he was appointed director of the social medicine division of the government-financed Medical Research Council. There he began his studies of exercise and heart risk.

Dr. Morris’s wife of 58 years, the former Galia Schuchalter, died in 1997. Besides his daughter, he is survived by a son, David; two grandchildren; and one great-granddaughter.

The studies that Dr. Morris started 60 years ago not only showed that those who exercised reduced the risk of heart attack but promoted the concept that those who had had a heart attack should exercise, said Dr. Kavanagh, the exercise science professor at the University of Toronto.

In 1973, seven heart-attack and bypass patients who had been rehabilitated by Dr. Kavanagh and his colleagues ran the Boston Marathon. Twelve years later, 20 other patients, including one with a transplanted heart, ran the marathon.

“Back in the ’60s and ’70s, once you had a heart attack you were sidelined; people thought your life expectancy was limited,” Dr. Kavanagh said. That changed, he said, because of the work of Dr. Morris and Dr. Paffenbarger, who did follow-up studies of longshoremen in Los Angeles. (Dr. Paffenbarger died in 2007.)

“Without their work we wouldn’t have had the groundwork to show that heart patients who exercise are less likely to have another attack,” Dr. Kavanagh said. “Those patients are no longer considered invalids.”

Almost every day, well into his mid-90s, Dr. Morris swam, pedaled his exercise bike or walked for at least half an hour.